Daily Report for 18th July 2012

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 14.6 °C (+0.1) 06:35 13.5 °C (-0.5) 18.9 °C (+4.4), 2025 11.2 °C (-3.3), 2010
Maximum Temperature 18.6 °C (-4.7) 00:01 19.4 °C (-3.6) 36.8 °C (+13.5), 2022 18.4 °C (-4.9), 2011
Mean Temperature 16.6 °C (-2.3) 16.2 °C (-2.0) 27.2 °C, 2022 15.1 °C, 2011
Minimum Humidity 71% 10:56 60% 71%, 2012 22%, 2016
Maximum Humidity 92% 07:45 92% 96%, 2024 70%, 2013
Mean Humidity 85% 79% 85%, 2012 48%, 2022
Minimum Pressure 1008 hPa 21:27 1008 hPa 1025 hPa, 2013 995 hPa, 2011
Maximum Pressure 1020 hPa 00:28 1014 hPa 1028 hPa, 2021 1000 hPa, 2011
Mean Pressure 1013 hPa 1011 hPa 1026 hPa, 2021 998 hPa, 2011
Mean Wind Speed 6.7 mph (+2.4) 5.1 mph (+0.8) 8.5 mph, 2009 1.1 mph, 2021
Maximum Wind Speed 13.7 mph 10:13 12.5 mph 19.3 mph, 2017 6.9 mph, 2018
Maximum Gust 19.7 mph 15:56 17.3 mph 31.0 mph, 2009 11.4 mph, 2021
Mean Wind Direction SW
Rainfall 1.7 mm 79.5 mm (298%) 11.7 mm, 2014
Maximum Hourly Rain 1.5 mm 17:40 6.0 mm, 2014
Maximum 10-min Rain 0.5 mm 17:23 4.5 mm, 2014
Maximum Rain Rate 3.2 mm/h 17:21 72 mm/h, 2014
Minimum Dew Point 12.2 °C 23:38 10.0 °C 13.2 °C, 2025 4.1 °C, 2010
Maximum Dew Point 15.6 °C 19:55 14.5 °C 20.8 °C, 2021 11.0 °C, 2015
Mean Dew Point 14.1 °C 12.3 °C 17.2 °C, 2021 7.9 °C, 2015
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 14.6 °C 06:37 13.7 °C 18.9 °C, 2025 11.2 °C, 2010
Day Maximum (09-21) * 18.2 °C * 15:22 19.3 °C 36.8 °C, 2022 18.2 °C, 2012
Max 10m Temp Rise 0.7 °C 09:50 0.6 °C 1.2 °C, 2009 0.5 °C, 2011
Max 1hr Temp Rise 1.7 °C 10:05 1.9 °C 4.6 °C, 2022 1.5 °C, 2019
Max 1hr Hum Rise 7% 11:58 10% 19%, 2009 6%, 2019
Max 10m Temp Fall 0.4 °C 02:31 0.6 °C 1.8 °C, 2009 0.4 °C, 2012
Max 1hr Temp Fall 1.4 °C 03:09 1.6 °C 4.6 °C, 2022 1.3 °C, 2019
Max 1hr Hum Fall 13% 10:14 12% 24%, 2022 10%, 2010
Max 10m Wind Speed 11.3 mph 16:19 10.5 mph 11.4 mph, 2011 4.2 mph, 2009
Minimum Feels-like 17.5 °C 06:19 15.6 °C 23.6 °C, 2025 11.2 °C, 2010
Maximum Feels-like 22.7 °C 00:03 22.2 °C 40.0 °C, 2022 20.6 °C, 2011
Mean Feels-like 20.0 °C 18.7 °C 30.2 °C, 2022 17.1 °C, 2011
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 4.0 °C (-4.7) 5.8 °C (-3.1) 21.4 °C (+12.7), 2022 4.0 °C (-4.7), 2012
Humidity Range 21% 32% 65%, 2014 21%, 2012
Pressure Range 12 hPa 6 hPa 12 hPa, 2012 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.1 [1%]49 hrs (42%) [18%] 14.6 [100%], 2016 0.1 [1%], 2012
Wet Hours 2
[Mean rain rate: 0.8 mm/h]		70 hrs (354%) [16%] 5, 2019 0, 2010
Cloud Cover Overcast
Events None
Comments 11-12, 1630-18 Light Showers
Extra Comments
Issues None known
Observer Absent? No
Pond Temperature @ Hampstead Heath 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 18th July 2012.
Times of extremes are computed using the midpoint of the longest continuous period at that extreme value.
Cumulative anomalies are reported according to the expected value for the month-to-date rather than month-end.
Sun hrs are derived based on analysis of webcam observations, but may use data from our closest site, Heathrow, when needed.
Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually.
Rainfall totals may be manually adjusted after the fact to correct delayed or erroneous data.
Cloud cover and Events are manually reported, often with multi-week delays.
Data is generally reliable and accurate but should always be viewed with some quantity of salt to hand.
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Daily Graph of Conditions

day graph

Webcam Summary of Cloud Conditions

daycamsum

Wind rose